Wednesday, August 2, 2017

Culture and the Human Mind

Kevin Laland, professor of behavioral and evolutionary
biology at the University of St. Andrews, presents an excellent and thorough
discussion of how human culture in feedback loops adapted the mind to tackle
ever increasing complex social and technological problems. While there are many
fine books on culture and evolution, such as P. Richerson and R. Boyd’s Not By Genes Alone, A. Mesoudi’s Cultural Evolution, M. Pagel’s Wired for Culture, and G. Hatfield and
H. Pittman’s Evolution of Mind, Brain,
and Culture, Laland’s book is both a product of decades of research in his
Lab and a result itself of cultural evolution, drawing from previous authors.
No one book should be read and relied on; students need a range of voices.
What’s different about Laland’s work is how, following the extended
evolutionary synthesis, he places emphasis on humanity’s (his word) unique (his
word) cognitive capabilities to develop a cultural mind through innovation,
teaching, high-fidelity copying, and learning. A worthwhile book to study, I’d
recommend this for anyone – across disciplines – interested in learning about
cultural evolution. Like others before him, Laland rightly believes biology can
explain some of our complex social systems and technology; indeed, he does
admirable work in a book filled with details and discussion on the science of
culture.

Let me summarize most of Laland’s extensive argument and
then get into some specifics. A cultural drive evolved through natural
selection via the benefits of precise copying. Human intelligence and cognition
increased because of many factors, ranging from better diets to sociality, and
subsequently cooperative learning increased. The reason human beings have such
complex culture is attributable to their high-fidelity copying, both maintained
and innovated on through social transmission and especially teaching. The
rising degree of social learning fed into conformist (i.e., cultural) norms.
From the emphasis on teaching, language probably evolved as an adaptation to
make teaching more effective. In this way, genes and culture co-evolved,
evident in the gradually increasing importance and spread of tool use and other
technologies across hominins. The gene/culture co-evolution feedback prompted
brain expansion and innovations that helped fuel, over hunter-gatherer
societies, agriculture and farming, which in turn led to cities. Subsequently,
the scale of physical and psychological cooperation exploded, demanding further
teaching and learning as well as division of labor and organized social
structures.

In Laland’s view, modern physical and artistic cultures have
not necessarily given any reproductive benefit. Likewise, he sees no sole
originator in the evolution of mind – rather, each new innovation enabled
cognitive feedbacks to engender yet more development. Though not discounting
our continuities with animal predecessors, Laland clearly sees us as special: He
often uses the adjective unique in
describing our humanity, a noun of
which he is fond. What seems to be different about us, according to Laland, is
our ability to teach. We don’t just assist or give aid to offspring and kin; we
actively engage in learning and instruction, keys to our massive neural
plasticity, innovations, and expansive niche construction. We maintain what
we’ve learned, share the information, and improve upon it through various
methods, all of which equate to cumulative culture.

In other words, our capacity for culture is probably
responsible for human intelligence and language. Innovative behaviors can
happen in other animals quickly, which means they are not traceable, as with
us, to genes but to simple learning. Of course the human career is a long
story, so Laland’s claim for human uniqueness and separation from other
primates includes the lineage from australopiths to anatomically modern humans.
In two words he narrowly sees any connection between us and nonhuman primates
as “superficial similarities” (15), and he insists on a rather large gap between us and even great apes. No
one would say we are chimpanzees.
Some human/chimpanzee genes don’t necessarily function similarly; and there are
no copies of some human genes in chimpanzees. Even down to the axon, the
splicing of genes can reveal considerable human/chimpanzee differences, notes
Laland, to say nothing of the switching on/off sequences of genes. The largest
difference of gene expression between humans and chimpanzees appears in the
brain and, Laland goes on, the chimpanzee brain is physiologically closer to a
monkey’s than to a human’s.

While he seems to paint a black-and-white picture here, a
key consideration is this: Early in our hominin lineage we were closer to a
great ape; our cultural creativity enabled the vast differences between us and
nonhuman primates over the course of millions of years. I should say, however,
that some studies (perhaps too recent to appear in Laland’s book?) point to
great ape full theory of mind. See, e.g., Christopher Krupenye, et al., 2016, (“Great
Apes Anticipate that Other Individuals Will Act According to False Beliefs.” Science 354.6308. 110-114) and
especially David Buttelmann, et al., 2017 (“Great Apes Distinguish Truth from
False Beliefs in an Interactive Helping Task.” Plos One 12.4. e0173793). Krupenye’s paper is co-authored by M.
Tomasello and J. Call, whom Laland relies on to stress what appear to be
black-and-white differences. But Laland’s overall point is, simply, that
hominin evolution clearly took several major upsurges as opposed to nonhuman
primates.

Laland, for instance, labels as remote
any indication of ape language, including those who’ve been taught to sign,
since they do not use grammatical syntax on their own. This, however, is
splitting a hair between intellectual capacity and ability. It almost seems
that in order to bolster his repeated claim of human uniqueness and superiority
Laland must lower the capacities (potentials) and abilities (actions) of
nonhuman primates. As one example,
Laland resists acknowledging any moral sensations in animals but yet admits to
their complex emotions. Emotional responses are directly tied to what we label
moral behavior. Contrary to his dismissing ape morality as “romantic” (24) we
need to admit, without using the problematic word morality, that nonhuman primates and especially great apes have
social intelligence and often exhibit caring, empathy, and most notably self-control.
No wonder, in my reading of Laland, he seems indifferent to the work of someone
like Frans de Waal. For instance, Laland says that emotions do not equate to
morals (25). While to some degree technically true, a good interdisciplinary study
that pairs moral philosophers with primatology on the moral senses could chip
away at that assessment. To support his claim, Laland cites numerous cases of
animal indifference to others, exploitation, or self-serving behavior. Surely,
we tend to be an overwhelmingly caring and helping species, but it’s inaccurate
to ignore our continual amount of maliciousness. The philosopher Arthur
Schopenhauer put it best in the early nineteenth century in his book On the Basis of Morality. Schopenhauer
talks about the difference between human beings and animals: We can be
maliciously harmful to one of our own species for no reason; we will
deliberately inflict pain, and not necessarily for our survival. So how does
that make us morally superior?

I quibble. At any rate, the bulk of
Laland’s argument deals with teaching and learning, both of which have achieved
incredible complexity not seen in other species. This is not to say there is no
social learning in apes for food resources, like termite fishing or nut
cracking. Bird species that migrate transmit directions to youngsters. Even in
the case of some fish species, one sex will copy another in mating behaviors.
Laland details these examples and some of the experiments he and his Lab team
conducted concerning guppies. Many fish learned by observing one demonstrate
the best route to food, in some cases even when the way to the food resource is
longer than another. This is social learning. In terms of predation, built-in
instinctual responses are not enough, for one must learn socially how to
elasticize responses to predators. For example, a rhesus monkey raised in
captivity does not fear snakes, which is one of its main predators in the wild.
So that’s a learned behavior.

Why copy, asks Laland. Not only to
learn but to socialize. There is asocial learning, where one works alone and
often makes mistakes, as in food theft. Asocial learning is costly but can
offer big payoffs. There is also social learning, important especially in
dealing with challenging environments. In social learning one garners
information second hand. For example, Laland tells us, birds and other species
learn to forage remnants of food resources directly acquired by another
species. While natural selection seems to favor the copying behaviors of social
learning, the asocial learners are crucial in discovering the actions to be
copied. For humans, Laland says social learning became strategic copying (56). Copying without innovation reduces costs.
It pays to see how well others benefit, or not, when exerting effort. If
current practices yield a low payoff, what are others doing to benefit
themselves?

There is game theory here, and Laland
and his team devised a tournament which revealed that observant social learning
over time paid off more/better than always trying to innovate. Asocial learning
tends to be beneficial under extreme circumstances. Importantly, though,
Laland’s Lab experiments, mathematical models, and aggregation of literature
reviews lay stress not on simple copying but on flexible, precision copying.
Good copies of copies ensure that if one successful strategist dies there’s a reliable
copy somewhere. These findings play out in long and well-written narratives
Laland offers, for instance, about stickleback fish and how they share and rely
on information from others. As per game theory, in some cases fish would copy
feeding habits more when they saw greater numbers of fish feeding at certain
locations. While Laland admits to learning and innovation across species, he
drives home the point that “humans alone” (102) have a monopoly on innovation.

Laland follows Allan C. Wilson: If
problem solving and copying are coded in the brain, then natural selection
would enlarge brains to be more innovative which, in turn, would further
increase brain structures. As Wilson generally predicted about intelligence
(innovation) and brain size, primates with larger brains are more flexibly
creative and copy each other more often. In this way tool use might have been a
feedback offshoot of gradually advancing social learning, which helps any
innovation spread. Selection would then favor the social learners, magnified by
the number of innovations, and so the feedback loops. Why big brains when even
honey bees can copy, asks Laland. His point is that larger brains do more than
make duplicates – they copy precisely and can even innovate from the copy.

In larger brained species, alternatives
come into play when copying, and this is related to sociality or attention to
the behavior and social nuances of others. A cultural drive begins to take hold
and is favored by natural selection since there are survival payoffs to
efficient copying with innovation. Hence, larger brains can facilitate problem
solving abilities, comprehension, and fast learning. Cutting against the modularity
of evolutionary psychology, Laland argues that there is high general
intelligence across social learning primate species: capuchins, baboons,
macaques, and great apes. The fundamental basis of primate intelligence,
Laland’s Lab concludes, consists of several elements selected for and cultural,
like infant dependence and learning, an extended life history, and activity in
a large group. In accord with Terrence Deacon, Laland reminds us that when
brains evolve parts once separate connect. A large brain is not essential for
social learning, but a larger brain permits better copying by allowing
different brain regions to communicate. Corvids, like apes, have large brains
relative to body size, with an enlarged frontal area. High-fidelity copying
favors ratcheting where innovations are improved upon. Laland’s mathematical
models suggest that precision copying advances significant change well beyond
local stimulus enhancement, typical for most species. Importantly, what’s
learned is passed on culturally and then tinkered with.

How is culture learned, asks Laland.
Through teaching, which is a vital adaptation for humans and related to
cultural cooperation. Many other species learn on their own without active
intervention. However, Laland says there is evidence that teaching (i.e., one’s
behavior is modified so as to instruct another) occurs in meerkats, ants, bees,
pied babblers, the superb fairy-wren, and possibly in cats, cheetahs, and
tamarins. Chimpanzees, in contrast says Laland, do not engage in teaching; one
observes and then works through trial and error. Since this type of social
learning is evolutionarily effective, it does not pay for adults to expend
costs in teaching. For humans, however, there is very little individual trial
and error learning and much more coaching via cumulative culture. Teaching is
evident in cooperative breeders: humans, ants, bees, meerkats, and pied
babblers. For example, human children will cooperate and demonstrate for each
other, in contrast to other primates like capuchins or chimpanzees.

An important component to Laland’s
argument is the evolution of language – there are connections in speech, mentality,
teaching, and learning. I particularly enjoyed the chapters on language and
gene/culture co-evolution, pivotal to claims centered in the book.
Communication for nonhuman primates is typically not learned and with little
change. Whereas other animals have somewhat fixed calls, our language needs to
be learned because the content is always changing. The cultural drive, Laland
explains, that ratchets complexity is dependent on teaching and learning,
bodily gestures and eye movements as well as verbal utterances; this
combination of subtleties in teaching is really only human. As part of the
extended evolutionary synthesis, language for our ancestors was the means to
instruct efficiently in a cultural niche dependent on learning.

According to Laland, language evolved
in terms of teaching and then broadened out to general cooperation. Moreover,
language is probably implicated in hierarchical, sequence structures or the
process of learning in stages. Here, too, Laland’s team worked on an extensive
human subject experiment to find that rather than imitation, education with
language most likely played a functional role in early Oldowan stone tool
manufacture. In turn, evincing gene/culture co-evolution, the use of the tools
would have favored selection for improved language, evident in more refined
Acheulean tools later. Laland offers a comprehensive explanation of some
examples of gene/culture co-evolution, such as right-handedness and lactose
tolerance: “culturally modified environments are capable of creating unusually
strong natural selection...” (216). Gene/culture co-evolution over sexual
selection accounts for changes to skin color, body shape, hair types, eye
colors, and even behaviors like mate choice. In fact, Laland says that
gene/culture co-evolution might be, for humans, the major form of evolution. To
recapitulate: Culture is teaching and learning, relates to tools and so
impacted hunting and butchering, which led to fire and cooking, and so expanded
the environmental range of hominins, and diversity across all of the preceding
increased cultural practices as the physical environment became controlled, not
threatening.

Key here is the rise of farming and
agriculture that permitted groups to expand into cultural societies. In
contrast, says Laland, hunter-gatherers have much less cultural evolution since
they are mobile, forage, and can’t carry around lots of goods. With a smaller
group there are, statistically, fewer innovating individuals. Agriculture, on
the other hand, became a critical niche construction. Certainly after the last
ice age a warmer climate was conducive to plant domestication, but there had
been warmer periods before and no other hominin species farmed. This means that
the rise of agricultural based societies was cultural and not environmental,
according to Laland, from a human mind that had been increasingly developing
technology and ecological knowledge to deal with the environment. It’s a long
story, told best by Laland over many pages, and there were health costs
associated with farming. But the advantages of being able to control large
volumes of food for many people outweighed costs. Hierarchical societies
emerged with a division of labor to increase productivity. In terms of selection, look at the
results, says Laland: Agriculturalists were able to do more than
hunter-gatherers, like expand populations, innovate more/better tools, and
create complex social structures. It’s difficult to discern if there is a value
judgment here (probably not), or if Laland is speaking only as a biologist. The
most famous example of a small group that lost its cultural know-how is the
Tasmanians, who, once separated from mainland Australia because of rising sea
levels about 10kya essentially lost their tool-kit knowledge.

In
terms of differential fitness, larger groups with more technology in a growing
feedback possess the means for variation and selective cultural inheritance.
Top this off with our immense capacity to cooperate and share norms of
behavior, and so we have the story of the human career and what Laland labels as
civilization. Groups that were more
technologically efficient and more cooperatively effective were selected over
others and thrived; surviving groups, in Laland’s schematic, were those who
consistently engaged in massive cultural transmission or the social teaching to
and learning by non-kin.

Laland
ends his book with a chapter on the arts, but it is too wide-ranging than some
others, like the outstanding chapter on cooperation. Eventually he focuses on
dance, which involves collaboration synchronization, but takes long to get to his
main ideas. Laland emphasizes dance because it includes music, visual effects,
and fashion, though he presents a recent, historical perspective that ignores
art in prehistory as cultural adaptation. While some authors might draw
continuities to other species, and demonstrated elsewhere in this book, Laland
pulls back. And for readers conversant in Paleolithic art and material cultures
from the long Pleistocene, this chapter might seem a bit thin – but it fits
nicely with the book, is well written and argued, and provides an important
capstone. Epitomized in dance is our complex culture that relies on the social
nature of learning, teaching, and cooperation.

In
a few words and to reiterate my opening, I highly recommend Kevin Laland’s book
Darwin’s Unfinished Symphony for
biologists and students in the humanities alike. After decades of work and
thought the book captures and explains in detailed, lucid prose important
findings in cultural evolution and the extended evolutionary synthesis.